Mechanisms Determining the Winter Atmospheric Response to the Atlantic Overturning Circulation
International audience In climate models, an intensification of the Atlantic meridional overturning circulation (AMOC) precedes a warming in the North Atlantic subpolar basin by a few years. In the IPSL-CM5A-LR model, this warming may explain the atmospheric response to the AMOC observed in winter,...
Published in: | Journal of Climate |
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Main Authors: | , , , |
Other Authors: | , , , , , , |
Format: | Article in Journal/Newspaper |
Language: | English |
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HAL CCSD
2016
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Online Access: | https://hal.sorbonne-universite.fr/hal-01331257 https://hal.sorbonne-universite.fr/hal-01331257/document https://hal.sorbonne-universite.fr/hal-01331257/file/Gastineau_2016_Mechanisms.pdf https://doi.org/10.1175/JCLI-D-15-0326.1 |
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openpolar |
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Open Polar |
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Université de Paris: Portail HAL |
op_collection_id |
ftunivparis |
language |
English |
topic |
Variability Models and modeling Climate models Geographic location/entity Sea ice Circulation/ Dynamics Meridional overturning circulation Atm/Ocean Structure/ Phenomena Stratosphere-troposphere coupling Multidecadal variability North Atlantic Oscillation [SDU.STU.CL]Sciences of the Universe [physics]/Earth Sciences/Climatology |
spellingShingle |
Variability Models and modeling Climate models Geographic location/entity Sea ice Circulation/ Dynamics Meridional overturning circulation Atm/Ocean Structure/ Phenomena Stratosphere-troposphere coupling Multidecadal variability North Atlantic Oscillation [SDU.STU.CL]Sciences of the Universe [physics]/Earth Sciences/Climatology Gastineau, Guillaume L’hévéder, Blandine Codron, Francis Frankignoul, Claude Mechanisms Determining the Winter Atmospheric Response to the Atlantic Overturning Circulation |
topic_facet |
Variability Models and modeling Climate models Geographic location/entity Sea ice Circulation/ Dynamics Meridional overturning circulation Atm/Ocean Structure/ Phenomena Stratosphere-troposphere coupling Multidecadal variability North Atlantic Oscillation [SDU.STU.CL]Sciences of the Universe [physics]/Earth Sciences/Climatology |
description |
International audience In climate models, an intensification of the Atlantic meridional overturning circulation (AMOC) precedes a warming in the North Atlantic subpolar basin by a few years. In the IPSL-CM5A-LR model, this warming may explain the atmospheric response to the AMOC observed in winter, which resembles a negative phase of the North Atlantic Oscillation (NAO). To firmly establish the causality links between the ocean and the atmosphere and illustrate the underlying mechanisms in this model, ensembles of atmosphere-only simulations are conducted, prescribing the SST and sea ice anomalies that follow an AMOC intensification. In late winter, the North Atlantic SST and sea ice anomalies drive atmospheric circulation anomalies similar to those found in the coupled model. Simulations only driven by the SST anomalies related to the AMOC show that the largest oceanic influence is due to the warm subpolar SST anomaly, which enhances the oceanic heat release and decreases the lower-tropospheric baroclinicity in the region of maximum eddy growth, resulting in a weaker meridional eddy heat flux in the atmosphere. The transient eddy feedback leads to a negative NAO-like response. An AMOC intensification is also followed by less sea ice over the Labrador Sea and more sea ice over the Nordic seas. The simulations with full boundary forcing suggest that such anomalies act to strengthen both the poleward momentum flux and the upward heat flux into the polar stratosphere and lead to a stratospheric warming, which then reinforces the negative NAO signal in late winter. |
author2 |
Processus de la variabilité climatique tropicale et impacts (PARVATI) Laboratoire d'Océanographie et du Climat : Expérimentations et Approches Numériques (LOCEAN) Muséum national d'Histoire naturelle (MNHN)-Institut de Recherche pour le Développement (IRD)-Université Pierre et Marie Curie - Paris 6 (UPMC)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-Institut Pierre-Simon-Laplace (IPSL (FR_636)) École normale supérieure - Paris (ENS-PSL) Université Paris Sciences et Lettres (PSL)-Université Paris Sciences et Lettres (PSL)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Institut national des sciences de l'Univers (INSU - CNRS)-Université Paris Diderot - Paris 7 (UPD7)-École polytechnique (X)-Centre National d'Études Spatiales Toulouse (CNES)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-École normale supérieure - Paris (ENS-PSL) Université Paris Sciences et Lettres (PSL)-Université Paris Sciences et Lettres (PSL)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Paris Diderot - Paris 7 (UPD7)-École polytechnique (X)-Centre National d'Études Spatiales Toulouse (CNES)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-Muséum national d'Histoire naturelle (MNHN)-Institut de Recherche pour le Développement (IRD)-Université Pierre et Marie Curie - Paris 6 (UPMC)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-Institut Pierre-Simon-Laplace (IPSL (FR_636)) Université Paris Sciences et Lettres (PSL)-Université Paris Sciences et Lettres (PSL)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Paris Diderot - Paris 7 (UPD7)-École polytechnique (X)-Centre National d'Études Spatiales Toulouse (CNES)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS) |
format |
Article in Journal/Newspaper |
author |
Gastineau, Guillaume L’hévéder, Blandine Codron, Francis Frankignoul, Claude |
author_facet |
Gastineau, Guillaume L’hévéder, Blandine Codron, Francis Frankignoul, Claude |
author_sort |
Gastineau, Guillaume |
title |
Mechanisms Determining the Winter Atmospheric Response to the Atlantic Overturning Circulation |
title_short |
Mechanisms Determining the Winter Atmospheric Response to the Atlantic Overturning Circulation |
title_full |
Mechanisms Determining the Winter Atmospheric Response to the Atlantic Overturning Circulation |
title_fullStr |
Mechanisms Determining the Winter Atmospheric Response to the Atlantic Overturning Circulation |
title_full_unstemmed |
Mechanisms Determining the Winter Atmospheric Response to the Atlantic Overturning Circulation |
title_sort |
mechanisms determining the winter atmospheric response to the atlantic overturning circulation |
publisher |
HAL CCSD |
publishDate |
2016 |
url |
https://hal.sorbonne-universite.fr/hal-01331257 https://hal.sorbonne-universite.fr/hal-01331257/document https://hal.sorbonne-universite.fr/hal-01331257/file/Gastineau_2016_Mechanisms.pdf https://doi.org/10.1175/JCLI-D-15-0326.1 |
genre |
Labrador Sea Nordic Seas North Atlantic North Atlantic oscillation Sea ice |
genre_facet |
Labrador Sea Nordic Seas North Atlantic North Atlantic oscillation Sea ice |
op_source |
ISSN: 0894-8755 EISSN: 1520-0442 Journal of Climate https://hal.sorbonne-universite.fr/hal-01331257 Journal of Climate, 2016, 29 (10), pp.3767-3785. ⟨10.1175/JCLI-D-15-0326.1⟩ |
op_relation |
info:eu-repo/semantics/altIdentifier/doi/10.1175/JCLI-D-15-0326.1 hal-01331257 https://hal.sorbonne-universite.fr/hal-01331257 https://hal.sorbonne-universite.fr/hal-01331257/document https://hal.sorbonne-universite.fr/hal-01331257/file/Gastineau_2016_Mechanisms.pdf doi:10.1175/JCLI-D-15-0326.1 |
op_rights |
info:eu-repo/semantics/OpenAccess |
op_doi |
https://doi.org/10.1175/JCLI-D-15-0326.1 |
container_title |
Journal of Climate |
container_volume |
29 |
container_issue |
10 |
container_start_page |
3767 |
op_container_end_page |
3785 |
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spelling |
ftunivparis:oai:HAL:hal-01331257v1 2024-05-19T07:43:36+00:00 Mechanisms Determining the Winter Atmospheric Response to the Atlantic Overturning Circulation Gastineau, Guillaume L’hévéder, Blandine Codron, Francis Frankignoul, Claude Processus de la variabilité climatique tropicale et impacts (PARVATI) Laboratoire d'Océanographie et du Climat : Expérimentations et Approches Numériques (LOCEAN) Muséum national d'Histoire naturelle (MNHN)-Institut de Recherche pour le Développement (IRD)-Université Pierre et Marie Curie - Paris 6 (UPMC)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-Institut Pierre-Simon-Laplace (IPSL (FR_636)) École normale supérieure - Paris (ENS-PSL) Université Paris Sciences et Lettres (PSL)-Université Paris Sciences et Lettres (PSL)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Institut national des sciences de l'Univers (INSU - CNRS)-Université Paris Diderot - Paris 7 (UPD7)-École polytechnique (X)-Centre National d'Études Spatiales Toulouse (CNES)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-École normale supérieure - Paris (ENS-PSL) Université Paris Sciences et Lettres (PSL)-Université Paris Sciences et Lettres (PSL)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Paris Diderot - Paris 7 (UPD7)-École polytechnique (X)-Centre National d'Études Spatiales Toulouse (CNES)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-Muséum national d'Histoire naturelle (MNHN)-Institut de Recherche pour le Développement (IRD)-Université Pierre et Marie Curie - Paris 6 (UPMC)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-Institut Pierre-Simon-Laplace (IPSL (FR_636)) Université Paris Sciences et Lettres (PSL)-Université Paris Sciences et Lettres (PSL)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Paris Diderot - Paris 7 (UPD7)-École polytechnique (X)-Centre National d'Études Spatiales Toulouse (CNES)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS) 2016-05 https://hal.sorbonne-universite.fr/hal-01331257 https://hal.sorbonne-universite.fr/hal-01331257/document https://hal.sorbonne-universite.fr/hal-01331257/file/Gastineau_2016_Mechanisms.pdf https://doi.org/10.1175/JCLI-D-15-0326.1 en eng HAL CCSD American Meteorological Society info:eu-repo/semantics/altIdentifier/doi/10.1175/JCLI-D-15-0326.1 hal-01331257 https://hal.sorbonne-universite.fr/hal-01331257 https://hal.sorbonne-universite.fr/hal-01331257/document https://hal.sorbonne-universite.fr/hal-01331257/file/Gastineau_2016_Mechanisms.pdf doi:10.1175/JCLI-D-15-0326.1 info:eu-repo/semantics/OpenAccess ISSN: 0894-8755 EISSN: 1520-0442 Journal of Climate https://hal.sorbonne-universite.fr/hal-01331257 Journal of Climate, 2016, 29 (10), pp.3767-3785. ⟨10.1175/JCLI-D-15-0326.1⟩ Variability Models and modeling Climate models Geographic location/entity Sea ice Circulation/ Dynamics Meridional overturning circulation Atm/Ocean Structure/ Phenomena Stratosphere-troposphere coupling Multidecadal variability North Atlantic Oscillation [SDU.STU.CL]Sciences of the Universe [physics]/Earth Sciences/Climatology info:eu-repo/semantics/article Journal articles 2016 ftunivparis https://doi.org/10.1175/JCLI-D-15-0326.1 2024-04-23T03:51:47Z International audience In climate models, an intensification of the Atlantic meridional overturning circulation (AMOC) precedes a warming in the North Atlantic subpolar basin by a few years. In the IPSL-CM5A-LR model, this warming may explain the atmospheric response to the AMOC observed in winter, which resembles a negative phase of the North Atlantic Oscillation (NAO). To firmly establish the causality links between the ocean and the atmosphere and illustrate the underlying mechanisms in this model, ensembles of atmosphere-only simulations are conducted, prescribing the SST and sea ice anomalies that follow an AMOC intensification. In late winter, the North Atlantic SST and sea ice anomalies drive atmospheric circulation anomalies similar to those found in the coupled model. Simulations only driven by the SST anomalies related to the AMOC show that the largest oceanic influence is due to the warm subpolar SST anomaly, which enhances the oceanic heat release and decreases the lower-tropospheric baroclinicity in the region of maximum eddy growth, resulting in a weaker meridional eddy heat flux in the atmosphere. The transient eddy feedback leads to a negative NAO-like response. An AMOC intensification is also followed by less sea ice over the Labrador Sea and more sea ice over the Nordic seas. The simulations with full boundary forcing suggest that such anomalies act to strengthen both the poleward momentum flux and the upward heat flux into the polar stratosphere and lead to a stratospheric warming, which then reinforces the negative NAO signal in late winter. Article in Journal/Newspaper Labrador Sea Nordic Seas North Atlantic North Atlantic oscillation Sea ice Université de Paris: Portail HAL Journal of Climate 29 10 3767 3785 |